Conventionally, this kind of control device, as wellknown, has a pair of first and second control levers supported swingably through one horizontal lever shaft at both sides of a plate-like fixing member fixed to the bicycle frame, a control wire is secured at one end to the first control lever, and a retaining mechanism, which positions the first control lever and holds it at its operated position and releases the second control lever, is provided between the respective levers and the fixing member so that, when the first lever swings in the direction of pulling the wire, the second lever swings in the direction of loosening the wire by a return spring, and, when the second lever swings in the direction of pulling the wire, the first lever swings to loosen the wire by a virtue of a return spring at the derailleur, thereby performing the two stage speed change.
This type of control device, however, may be operated improperly and malfunction because the two levers operating in the same direction and also it creates a problem in that a cyclist's finger operating one lever may to be hit by the other which springs back by action of the return spring.